• Korean Journal of Materials Research
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• v.6 no.2
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• pp.158-165
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• 1996

열증착기(thermal evaporator)로 증착시킨 Cu를 상온에서 3.5M CuCl2+0.5M HCI+0.5MKCI 용액을 사용하여 습식각하고 2일간 대기중 노출시킨 후 X-선 광전자 분광기를 이용하여 표면의 결합상태를 관찰하였다. 그 결과 습식식각된 Cu 표면에서는 C, O, Ci 및 Cu가 존재함을 알 수 있었다. 표면원소에 대한 오제이 전자 스펙트라(Auger electron spectra)와 광전자 스펙트라(photoelectron spectra)의 정량적인 비교를 통하여 표면의 모든 결합상태를 확인할 수 있었고 그 상대적인 양까지도 얻어낼 수 있었다. 식각된 Cu의 표면에는 Cu-Cu, 2Cu-O, Cu-Ci, Cu-2(OH), 및 Cu-2Cl의 결합상태가 존재함을 알 수 있었고, CuLMMAuger line spectrum의 관찰을 통하여 계산된 각 결합의 정량적인 비교를 검증할 수 있었다. 따라서 chemical shift가 거의 관찰되지 않아 결합상태 분리가 불가능한 식각된 구리표면의 정량적 결합상태는 각 결합상태의 상대적 비교를 통하여 얻어질 수 있음을 알 수 있었다.

• Applied Chemistry for Engineering
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• v.7 no.4
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• pp.639-644
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• 1996

The $YBa_2Cu_{3-y}Ag_yO_{7-x}$ high-temperature superconductors were prepared by pyrophoric synthetic method from $Y_2O_3$, $BaCO_3$, CuO, and $AgNO_3$ powders. When we were partially substituted Ag for Cu in $YBa_3Cu_3O_{7-x}$, the superconducting properties of $YBa_2Cu_{3-y}Ag_yO_{7-x}$ were investigated with X-ray diffractometer, resisitivity measuring equipment, SEM, and Vickers Hardness. The Tc,zero of $YBa_2Cu_3O_{7-x}$ was 91K, the density was $5.2g/cm^3$, and the hardness was $590kg/mm^2$. When Ag was substituted below y=0.15, electrical property of $YBa_2Cu_{3-y}Ag_yO_{7-x}$ did not change but microstructure, density, and hardness were enhanced.

• Korean Journal of Materials Research
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• v.14 no.12
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• pp.829-834
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• 2004

Annealing of $Cu(B)/Ti/SiO_2$ in vacuum has been carried out to investigate the effects of Ti underlayer on microstructure in $Cu(B)/Ti/SiO_2$ structures. For comparison, $Cu(B)/Ti/SiO_2$ structures was also annealed in vacuum. Three different temperature dependence of Cu growth can be seen in $Cu(B)/Ti/SiO_2$; B precipitates- pinned grain growth, abnormal grain growth, normal grain growth. The Ti underlayer having a strong affinity for B atoms reacts with the out-diffused B to the Ti surface and forms titanium boride at the Cu-Ti interface. The formation of titanium boride acts as a sink for the out-diffusion of B atoms. The depletion of boron in grain boundaries of Cu films, as results of the rapid diffusion of B along the grain boundaries and the insufficient segregation of B to the grain boundaries, induces grain boundaries to migrate and causes the abnormal grain growth. The increased bulk diffusion coefficient of B within Cu grains can be responsible for the normal grain growth occurring in the annealed $Cu(B)/Ti/SiO_2\;at\;600^{\circ}C$. In contrast, the $Cu/SiO_2$ structures show only the abnormal growth of grains and their sizes increasing as the temperature increases above $400^{\circ}C$.

• Bulletin of the Korean Chemical Society
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• v.28 no.10
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• pp.1781-1786
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• 2007

Two copper(II) complexes, [CuL3](ClO4)2 bearing one N-CH2CH2CONH2 group as well as one N-CH2CH2CN group and [CuL4](ClO4)2 bearing two N-CH2CH2CONH2 groups, have been prepared by the selective hydrolysis of [CuL2](ClO4)2 (L2 = C-meso-1,8-bis(cyanoethyl)-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane). The complex [CuL5](ClO4)2 bearing one N-CH2CH2C(=NH)OCH3 and one N-CH2CH2CN groups has been prepared as the major product from the reaction of [CuL2](ClO4)2 with methanol in the presence of triethylamine. In acidic aqueous solution, the N-CH2CH2C(=NH)OCH3 group of [CuL5](ClO4)2 undergoes hydrolysis to yield [CuL6](ClO4)2 bearing both N-CH2CH2COOCH3 and N-CH2CH2CN groups. The crystal structure of [CuL5](ClO4)2 shows that the complex has a slightly distorted square-pyramidal coordination polyhedron with an apical Cu-N (N-CH2CH2C(=NH)OCH3 group) bond. The apical Cu-N bond distance (2.269(3) A) is ca. 0.06 A longer than the apical Cu-O (N-CH2CH2CONH2 group) bond of [CuL4](ClO4)2. The pendant amide group of [CuL3](ClO4)2 is involved in coordination. The carboxylic ester group of [CuL6](ClO4)2 is also coordinated to the metal ion in various solvents but is removed from the coordination sphere in the solid state.

• Journal of the Microelectronics and Packaging Society
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• v.20 no.2
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• pp.47-51
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• 2013

Chemical mechanical polishing (CMP) has become one of the key processes in wafer level stacking technology for 3D stacked IC. In this study, two-step CMP process was proposed to polish $Cu/SiO_2$ hybrid bonding surface, that is, Cu CMP was followed by $SiO_2$ CMP to minimize Cu dishing. As a result, Cu dishing was reduced down to $100{\sim}200{\AA}$ after $SiO_2$ CMP and surface roughness was also improved. The bonding interface showed no noticeable dishing or interface line, implying high bonding strength.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.154-154
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• 2003

A stoichiometric mixture of evaporating materials for CuGaSe2 single crystal thin films was prepared from horizontal electric furnace. Using extrapolation method of X-ray diffraction patterns for the polycrystal CuGaSe2, it was found tetragonal structure whose lattice constant at and co were 5.615 ${\AA}$ and 11.025 ${\AA}$, respectively. To obtain the single crystal thin films, CuGaSe2 mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the hot wall epitaxy (MWE) system. The source and substrate temperatures were Slot and 450$^{\circ}C$, respectively. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (UXD). The carrier density and mobility of CuGaSe2 single crystal thin films measured with Hall effect by van der Pauw method are 5.0l${\times}$10$\^$17/ cm$\^$-3/ and 245 $\textrm{cm}^2$/V$.$s at 293K, respectively. The temperature dependence of the energy band gap of the CuGaSe2 obtained from the absorption spectra was well described by the Varshni's relation, Eg(T) = 1.7998 eV - (8.7489${\times}$10$\^$-4/ eV/K)T$^2$/(T + 335 K. After the as-grown CuGaSe2 single crystal thin films was annealed in Cu-, Se-, and Ca-atmospheres, the origin of point defects of CuGaSe2 single crystal thin films has been investigated by the photoluminescence(PL) at 10 K The native defects of V$\_$CU/, V$\_$Se/, Cu$\_$int/, and Se$\_$int/ obtained by PL measurements were classified as a donors or accepters type. And we concluded that the heat-treatment in the Cu-atmosphere converted CuGaSe2 single crystal thin films to an optical n-type. Also, we confirmed that Ga in CuGaSe2/GaAs did not form the native defects because Ga in CuGaSe2 single crystal thin films existed in the form of stable bonds.

• Journal of the Microelectronics and Packaging Society
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• v.29 no.2
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• pp.73-79
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• 2022

In this study, a reaction study between Ga, which has recently been spotlighted as a low-temperature bonding material, and Cu, a representative electrode material, was conducted to investigate information necessary for low-temperature soldering applications. Interfacial reaction and intermetallic compound (IMC) growth were observed and analyzed by reacting Ga and Cu/Au substrates in the temperature range of 80-200℃. The main IMC growing at the reaction interface was CuGa₂ phase, and AuGa₂ IMC with small particle sizes was formed on the upper part and Cu₉Ga₄ IMC with a thin band shape on the lower part of the CuGa₂ layer. CuGa₂ particles showed a scallop shape, and the particle size increased without significant shape change as the reaction time increased, similar to the case of Cu₆Sn₅ growth. As a result of analyzing the CuGa₂ growth mechanism, the time exponent was calculated to be ~3.0 in the temperature range of 120-200℃, and the activation energy was measured to be 17.7 kJ/mol.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.4 no.2
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• pp.148-156
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• 1994

Three composition in the system of $YO_{1.5}-BaO-CuO$ were grown using a cold crucible (skull) melting technique with a 50 kW R.F. induction generator operating at 4 MHz as the power source. The starting materials were prepared by conventional ceramic powder processing methods, loaded into the skull, and melted at about $1200^{\circ}C$. For this study, compositions near the $YBa_2Cu_3O_X$ region were selected. The growth rates used ranged from 4 cm/hr to 0.25 cm/hr. The relation between the microstructures and the starting composition of each ingot was determined using metallograph, X-ray diffraction, and energy dispersive X-ray analysis. Both $YBa_2Cu_3O_X$ and $Y_2BaCuO_5$ needle-shaped crystals, aligned with the growth direction, were formed in the $CuO-BaCuO_2$ eutectic matrix of the $YBa_2Cu_7O_x and YBa_5Cu_{11}O_x$ ingot.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.11a
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• pp.109-112
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• 1995

CuInS$_2$thin film was prepared by heat treatment at vacuum 10$\^$-3/ Torr of S/In/Cu stacked layer which was deposited by sequential. And so, the polycrystalline CuInS$_2$with chalcopyrite structure was well made at heat treatment temperature of 250$^{\circ}C$ and heat treatment time of 60 min. Single phase of CuInS$_2$was formed from Cu/In composition ratio of 0.84 to 1.3. p conduction type of CuInS$_2$thin film was appeared from Cu/In competition ratio of 0.99. The highest resistivity of CuInS$_2$with p type was 1.608${\times}$10$^2$$\Omega$cm at Cu/In composition ratio of 0.99 and The lowest resistivity was 5.587${\times}$10$\^$-2/$\Omega$cm at Cu/In composition ratio of 1.3.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.152-153
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• 2007

$CuInSe_2$ single crystal thin film was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the hot wall epitaxy (HWE) system. After the as-grown $CuInSe_2$ single crystal thin films was annealed in Cu-, Se-, and In-atmospheres, the origin of point defects of $CuInSe_2$ single crystal thin films has been investigated by the photoluminescence(PL) at 10 K. The native defects of $V_{Cu}$, $V_{Se}$, $Cu_{lnt}$, and $Se_{lnt}$ obtained by PL measurements were classified as a donors or acceptors type. And we concluded that the heat-treatment in the Cu-atmosphere converted $CuInSe_2$ single crystal thin films to an optical n-type. Also, we confirmed that In in $CuInSe_2$/GaAs did not form the native defects because In in $CuInSe_2$ single crystal thin films existed in the form of stable bonds.